Platinum. Bayonetta, Madworld, Vanquish, Infinite Space and now Anarachy Reigns, all released within three years.

Insomniac. They keep on pumping out games right left and center. 

Probably either Nintendo or Sony's 1st parties.

Without a doubt not Bioware, I played that Sonic RPG and was heavily disapointed in it.  

Either Nintendo (releasing some of the best games of all time, new genres, revivals, new IPs), Sega (lots of good games, all consoles, new IPs), or Capcom (Resident Evil, Monster Hunter, Street Fighter...)

All 3 are amazing devs this gen, and deserved to be recognised for the quality of their games

I would say either Level-5, Armor Project or VanillaWare.

Level-5 of course has done a ton.  Professor Layton, Inazuma Eleven, Dragon Quest IX, White Knight Chronicles.  And now they've teamed up with Ghibli Animation Studios and are making both a PS3 and DS RPG set i nthe world of Miyazaki.  If that wasn't enough, they've already announced 4 3DS games.

VanillaWare may not have the quantity of games of other compaies, but no one can argue their quality isn't through the roof.  For a small independant game studio whose games only sell about 200,000-400,000 each, they have made some of the best games this gen.  Including Muramasa: The Demon Blade for Wii and an upcoming PSP RPG.

Armor Project focuses completely on one series: Dragon Quest.  But in just this gen, they have overseen the development of 10 different Dragon Quest games, with every single title improving on its predecessors with new features, updated graphics and some of the best innovation in the series to date.

effort =/= quality

Insomniac have really been developing quickly - five games in this generation alone, and of those, Resistance 2 was the only real miss.

Notch .... one man against the world hah  ... really its all in what you think makes a good game. if the dev makes games that appel to you, you will follow them i would have said pandimic as i have loved all the games they made this gen but ea shut them down. the battelfield guys seem to be doing well i loved BF:bc, BF:BC2 single player took a hit due to the be like MW thing, but still fun

Dragon age took 7 years of development time, and recently released DA2 is rushed buggy mess full of reused assets.

I'd say Naughty Dog they are bringing top notch quality games every 2 years without overmilking those titles like happens for CoD.

Also Dice is great regularly making good games and offering regular after-sales support.

you are talking about Bioware consisting of about 3 studios all pretty large.